Insight detects a strong meteorite impact on Mars

Oct. 28 () –

A magnitude 4 tremor recorded last December 24 by NASA’s InSight module on Mars corresponded to the impact of one of the largest meteorites seen so far on the red planet.

Cameras aboard MRO (Mars Reconnaissance Orbiter) detected the huge new crater from space. The meteoroid excavated boulder-sized chunks of ice buried closer to the Martian equator than ever before, a discovery with implications for NASA’s future plans to send astronauts to the Red Planet.

Scientists determined the quake was due to a meteorite impact when they looked at before-and-after images from NASA’s Mars Reconnaissance Orbiter (MRO) and spotted a huge new crater. Offering a rare opportunity to see how a huge impact shook the ground on Mars, the event and its effects are detailed in two articles now published. in Science magazine.

A STRONG IMPACT

The meteoroid is estimated to have been 5 to 12 meters long, small enough to have burned up in Earth’s atmosphere, but not in Mars’ thin atmosphere, which is only 1% denser than our planet’s. The impact, in a region called Amazonis Planitia, opened a crater approximately 150 meters wide and 21 meters deep. Some of the ejecta thrown up by the impact flew up to 37 kilometers away.

With images and seismic data documenting the event, this is believed to be one of the largest craters ever seen anywhere in the solar system. There are many larger craters on the Red Planet, but they are significantly older and predate any mission to Mars.

“It is unprecedented to find a new impact of this size,” he said. it’s a statement Ingrid Daubar of Brown University, who leads InSight’s Impact Science Working Group. “It’s an exciting time in geological history, and we have to witness it.”

InSight has seen its power drop dramatically in recent months due to a buildup of dust on its solar panels. The spacecraft is now expected to shut down in the next six weeks, ending mission science.

InSight is studying the planet’s crust, mantle and core. Seismic waves are key to the mission and have revealed the size, depth and composition of the inner layers of Mars. Since it landed in November 2018, InSight has detected 1,318 earthquakes, including several caused by smaller meteorite impacts.

But the earthquake that resulted from last December’s impact was the first observed to have surface waves, a kind of seismic wave that ripples along the top of a planet’s crust. The second of two Science papers related to the big impact describes how scientists They use these waves to study the structure of the Martian crust.

In late 2021, InSight scientists informed the rest of the team that they had detected a major earthquake on December 24. The crater was first seen on February 11, 2022, by scientists working at Malin Space Science Systems (MSSS), which built and operates two cameras aboard MRO. The Context Camera (CTX) provides medium-resolution black-and-white images, while the Mars Color Imager (MARCI) produces daily maps of the entire planet, allowing scientists to track large-scale climate changes. like the recent regional dust storm that further diminished InSight’s solar power.

The impact blast zone was visible in the MARCI data that allowed the team to pinpoint a 24-hour period within which the impact occurred. These observations were correlated with the seismic epicenter, which conclusively proves that a meteorite impact caused the great earthquake of December 24.

“The impact image was unlike anything I had seen before, with the huge crater, exposed ice and dramatic blast zone preserved in the Martian dust,” said Liliya Posiolova, who heads the Orbital Science and Operations Group at MSSS. “I couldn’t help but imagine what it must have been like to witness the impact, the atmospheric explosion and the debris ejected miles below.”

Establishing the rate at which craters appear on Mars is critical to refining the planet’s geological timeline. On older surfaces, like those of Mars and our Moon, there are more craters than on Earth; On our planet, the processes of erosion and plate tectonics erase the oldest features on the surface.

The new craters also expose materials below the surface. In this case, MRO’s High Resolution Imaging Science Experiment (HiRISE) color camera he saw large chunks of ice scattered from the impact.

Underground ice will be a vital resource for astronauts, who could use it for a variety of needs, including drinking water, agriculture, and rocket propellant. Ice has never been seen buried so close to the Martian equator, which, as the warmest part of Mars, is an attractive place for astronauts.